Finite element modelling and simulation of drying isotropic and anisotropic food samples

Soydan Karabacak, Meltem
The aim of this study was to investigate drying characteristics (temperature gradient, rate of drying and temperature change, drying time, diffusivity values, shrinkage) of isotropic and anisotropic foods by observing the changes in temperatures at four different locations and moisture contents and to build an appropriate model for simulation of temperature and moisture distribution using finite element method. The lean meat samples (anisotropic) with three fiber configurations (v; flow normal to fiber, drying along the fiber, h1; flow normal to fiber, h2; flow along to fiber) and minced meat (isotropic) were dried at two different temperatures (48°C, 70°C) and three different velocities (0.5, 1.0, 1.7 m/s) of air. Rate of temperature change was found as minced>h2>v≈h1 while rate of drying was observed as h2≈v>h1>minced. The order of temperature gradient through the lean meat samples was v<h2<h1. Minced meat showed 1.0-4.4°C higher temperature values but 2.3-6.2% lower moisture loss than the lean meat in all fiber configurations. A model based on nonlinear coupled heat and mass transfer considering evaporation due to change in overall moisture content through the sample was found more appropriate than the model considering evaporation loss only at the surface. The diffusion coefficients for lean and minced meat were expressed as a function of temperature and moisture content. At 70°C air temperature, shrinkage should be included in the model. As a result, finite element modelling considering both anisotropic thermal conductivity and diffusivity definitions showed good agreement with experimental data and represented anisotropy effect successfully.


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Citation Formats
M. Soydan Karabacak, “Finite element modelling and simulation of drying isotropic and anisotropic food samples,” Ph.D. - Doctoral Program, Middle East Technical University, 2013.